System and method for monitoring and delivering therapeutics to the spinal cord

ABSTRACT

This invention is a continuous monitor of the spinal cord and brain microenvironment in injury and disease that also allows therapeutic interventions. It utilizes a multiport catheter that contains a transducer at the tip for monitoring spinal physiological parameters and also allows via additional ports for sampling and exchange of spinal fluid, as well as drug delivery to the central nervous system. This invention allows for more precise therapeutic interventions in spinal cord and brain injury and disease. If the pressure monitor is mounted to the patient, the wireless data transmitter may also send a wireless signal to a wireless data receiver for display on a wireless data display. The catheter would allow for wireless transmission of physiological parameters.

This application claims priority from co-pending application Ser. No. 11/840,213 filed Aug. 16, 2007 by the same inventor Milan Radojicic which in turn claims priority from provisional patent application Ser. No. 60/822,640, filed Aug. 17, 2006.

DISCUSSION OF RELATED ART

The present invention relates generally to surgical methods and medical devices. More particularly, it concerns methods and devices for monitoring and delivering therapeutics to the spinal cord and brain along a spinal fluid pathway or cistern, particularly the lumbar cistern.

By the end of the next decade, 300,000 people will be living with chronic spinal cord injury in the US alone. Advances in medical and rehabilitative care have improved survival rates for these individuals, but many experience clinical decline even years after the initial injury. Clinical decline is often accompanied by a slow and progressive cavitation of the central spinal cord, known as post-traumatic syringomyelia. The pathogenesis of this disease remains poorly understood, but may be related to spinal cord edema and altered intraspinal pressure due changes in spinal fluid homeostasis. Beyond spinal cord injury, other spinal cord diseases may similarly be impacted by such pathophysiological processes. Such diseases include spinal tumors and vascular malformations, spinal infections, multiple sclerosis, transverse myelitis, and non-traumatic syringomyelia. Moreover, considerable morbidity and mortality may result from spinal surgical interventions where monitoring has been heretofore limited to the electrophysiological parameters.

Following spinal cord injury and disease, normal CSF dynamics may be distorted by a number of possible mechanisms, including subarachnoid CSF outflow obstructions, changes in compliance of the subarachnoid space, or elevated intraspinal pressures. Altered CSF dynamics are believed to result in localized spinal cord edema, known as the presyrinx state that subsequently gives rise to central canal dilation and/or the formation of intraspinal glial-lined parenchymal cysts.

The propagation of intraspinal cavities requires a driving force sufficient to propel fluid via a one-way valve mechanism into the cysts, which often contain fluid at a higher pressure than the subarachnoid space. Proposed driving forces include cardiac pulsations along vessels, postural changes and valsalva movements and elevated intraspinal pressures. Perhaps, transient hypertensive episodes of autonomic dysreflexia is a potential driving force.

The measurement and treatment of raised intracranial pressures following insults to the brain is very well established and is based on many years of work in experimental neurology establishing a pressure-volume relationship in cranial compartment, first suggested by Alexander Monro in 1783. With the increasing recognition on the role of spinal edema, pressure and altered cerebrospinal fluid dynamics on spinal cord injury and disease, there has been a long felt need in the industry for monitoring such phenomena. Indeed, continuous monitoring of various physiological parameters is a mainstay of modern critical care. Prior art has focused on intracranial pressure monitoring, for example see Beckman et al. U.S. Pat. No. 5,325,865. Purdy et al. U.S. Pat. No. 7,150,737 B2 would allow for navigating the subarachnoid space, but limit interventions to heating and cooling of the nervous tissue. Thus, an object of the invention is to provide continuous monitoring of several spinal physiological parameters, along with a method of drug delivery and therapeutics.

A variety of catheter structures have been created for cycling fluid, such as Mahurkar in U.S. Pat. No. 4,583,968 issued Apr. 22, 1986 the disclosure of which is incorporated herein by reference. The Mahurkar catheter provides an elongated cylindrical tube for injection and removal of fluid. Unfortunately, the Mahurkar catheter provides an uncomfortable configuration for user. Another dual lumen catheter is discussed by Macoviak in U.S. Pat. No. 5,827,237 issued Oct. 27, 1998, the disclosure of which is incorporated herein by reference. The Macoviak catheter is specially shaped and specialized for heart surgery.

SUMMARY OF THE INVENTION

The present invention involves introducing a catheter in an interspace of the spine. FIG. 1 shows typical parts needed for insertion of a catheter. A scoop shaped toughey needle which is a large gauge needle is first inserted into the interspace with the elongated oval tip opening facing upward. A guide wire is inserted through the toughey needle and gently placed in the epidural space. The guide wire guides a transducer tipped catheter into the epidural space through the interspace. A stopcock plugs the catheter during insertion. After the catheter is introduced, the guide wire and needle are both removed. FIG. 2 shows the catheter introduced. After the catheter is introduced, the patient lays down as seen in FIG. 3. While the patient is laying down, the transducer provides monitoring of changes in pressure and physiological parameters of the cerebrospinal fluid. Optionally, spinal fluid can be exchanged in a spinal cord dialysis. Also, therapeutics and drug delivery can be introduced via the catheter. Drug delivery can be pain medicine or anti-inflammatory medicine, or any other type of medicine. Pain medicine is desirable since having a catheter inserted in epidural space between spinal cord and bones is typically not very comfortable, see FIG. 5.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of standard equipment necessary for introducing a catheter.

FIG. 2 is a diagram of a catheter introduced the L4-L5 interspace.

FIG. 3 is a diagram of a patient laying on a table with real-time spinal cord monitoring and therapeutics.

FIG. 4 is a diagram showing pressure monitoring, spinal fluid analysis monitoring, drug delivery and spinal fluid exchange options available after insertion of the catheter.

FIG. 5 is a diagram showing catheter introduction into the epidural space between spinal cord and bones.

FIG. 6 is a diagram of a transducer tipped catheter.

FIG. 7 is a diagram of a four section transducer tipped catheter.

FIG. 8 is a diagram of a wireless embodiment.

The following call a list of elements is consistently used throughout the drawings.

-   1 First Chamber -   2 Second Chamber -   3 Third Chamber -   4 Fourth Chamber -   20 Fluid Apertures -   21 Fluid inflow apertures -   22 Fluid outflow apertures -   25 Transducer -   30 Catheter -   40 Pressure Monitor -   45 Fluid Pump -   47 Pressure Status Display -   48 Spinal Fluid Analysis Data -   50 Medication -   55 Spinal Fluid Exchange Apparatus -   65 Sleeve -   66 Four Tubes -   70 Wireless Data Transmitter -   71 Wireless Data Receiver -   73 Wireless Data Display -   75 Wireless Signal -   87 Tip Opening -   88 Axial Segmentation Dividing Panels -   89 Surgical Tool -   90 Spinal Fluid Exchange Device -   95 Dialyzer -   100 Tip Section -   200 Middle Section -   300 Rear Section

DETAILED DESCRIPTION OF THE INVENTION

This invention allows a continuous monitoring of the spinal cord and brain microenvironment for injury and disease that also allows therapeutic interventions. The device utilizes a multiport catheter that contains a transducer at the tip for monitoring spinal physiological parameters and also allows via additional ports for sampling and exchange of spinal fluid, as well as drug delivery to the central nervous system. This catheter would also allow for introduction of surgical tools. This invention allows for more precise therapeutic interventions in spinal cord and brain injury and disease. Generally, there is a tip section 100, a middle section 200, and a rear section 300. The tip section 100 is preferably translucent or transparent and is made of soft material such as silicone or elastomeric material. It may have an opening for surgical instruments. The tip section is attached to a middle section 200 which has a number of openings on the sidewall for cycling, suctioning or injecting liquid in a very localized area, as well as extended cycling and dialysis of ceresbrospinal fluid along the extent of the craniospinal axis. The middle section in the best mode is approximately 0.5 to 3 inches long in a quadrant cross-section configuration. The rear section 300 is a long line that runs from the patient back to medical machines. The rear section 300 can be made of four tubes bundled inside an outside tube that acts as a sleeve. The sleeve 65 and the three sections can be press fit together, or ultrasonically welded, or glued together.

A catheter 30 typically has a circular cross-section and in this case can include a transducer tip 25. The catheter 30, FIG. 7 is segmented into preferably four separate chambers 1, 2, 3, 4 that have openings on an external periphery. The segmentation when seen in cross-section provides a first chamber 1, a second chamber 2 to the right of the first chamber, a third chamber 3 below the second chamber, and a fourth chamber 4 to the left of the third chamber. Each of the chambers are formed by axial segmentation dividing panels 88 formed within the multiport catheter. The panel configuration could be linear, or radial or axial. The panels are connected to the catheter and are preferably formed of the same type of material, such as biocompatible material suitable for insertion along a spinal fluid pathway that would minimize patient discomfort. The multiport catheter shown therefore has two pairs of an equal sized arc shaped segmented body that connects to two pairs of tubing. The catheter 30, FIG. 7 has the second and third chambers 2, 3 dedicated to flow of spinal fluid. The spinal fluid may flow in either direction. The second chamber may allow fluid to enter and to the third chamber may allow the fluid to exit. Alternatively, the second chamber may allow the fluid to exit and the third chamber may allow the fluid to exit. The plurality of apertures on the second chamber can be round or oval-shaped as shown in the drawing. The first chamber may also have a plurality of apertures for receiving spinal fluid. Alternatively, the first chamber may be used to feed an electrical wire to a pressure sensor in the tip of the catheter.

This catheter would also allow for monitoring of physiological parameters of the spinal fluid, either locally (via a sensor at the tip of catheter) or externally. If the data is locally obtained, this spinal fluid data could be transmitted wirelessly. This could be helpful in a situation where the catheter is attached to a subcutaneous drug pump. The wireless monitoring of spinal fluid data could help predict a developing infection and prompt appropriate medical intervention.

The axial segmentation dividing panels 88 provides a quadrant configuration which provides a fourth port 4 which is a spare port capable of receiving a surgical tool 89 which passes through the spare port to an opening in the tip called a tip opening 87. The tip is a pressure sensor which has a passageway through it connected to the fourth spare port for allowing a surgical tool to pass through the tip of the device. The monitoring port which is the first port, and can receive a transducer wire for passing patient data signals from the monitoring port to the physician. The cap can be made of a transparent material allowing the monitoring port to receive a fiber-optic line for a camera, an ultrasonic or infrared receiver for viewing the patient. The monitoring port is large enough to receive the fiber-optic line as well as the electrical wire for the transducer.

Additionally, a fluid pump 45 can circulate spinal fluid. The fluid pump 45 can be automatically deactivated when measuring pressure at a pressure monitor 40. Pressure monitoring provides a real-time pressure status display 47. Additionally, spinal fluid analysis data 48 can also be displayed on the status display 47. Additionally, medication 50 can be delivered through the fluid pump 45 driving medication through the catheter. Additionally, spinal fluid exchange may incorporate a spinal fluid exchange apparatus allowing spinal cord dialysis.

Sometimes, not all the lumens need to be of the same structure. For example, the multiple lumen catheter with an elongated cylindrical tube having an internal diametral septum extending along the length thereof can form a pair of major lumens having semicircular transverse cross-sections with a small third lumen. Mahurkar in U.S. Pat. No. 5,221,256 provides a method for making three lumens with two of them larger and one of them smaller, the disclosure of which is incorporated herein by reference. The present invention may use the Mahurkar multiple lumen structure with the smaller third lumen hooked up to electrical wire, while the two larger lumens transport liquid. The tube connection to the multiple port catheter provides a variety of options for the physician. Alternatively, if the third lumen is for a surgical tool pathway that is too big for the small lumen configuration, the multiple lumen catheter could be made in the configuration of Mahurkar's crescent shaped configuration as shown in U.S. Pat. No. 5,378,230 issued Jan. 3, 1995, the disclosure of which is incorporated herein by reference. The Mahurkar's crescent shaped configuration makes the in and out lumens smaller and the third lumen bigger. In any case, there are a wide variety of geometric configurations commonly and commercially available for configuring the lumens. The best mode is to have the lumens of the catheter configured as four axially symmetrical pie shaped quadrants oriented 90° to each other.

The second step is to insert a transducer tipped catheter in an interspace of the spine, but the first step is to select and configure the transducer. The catheter, FIG. 6 is a multi-port catheter with holes or apertures for CSF outflow and inflow, pressure monitoring and an additional unused port. The configuration of the transducer allows a variety of tools to be introduced through the multiport catheter. Each port terminates at a chamber of the transducer mounted at the tip of the catheter. In the four chamber embodiment, the first pair of chambers can be used for cycling spinal fluid. The second pair of chambers can be used for pressure monitoring, pressure sensor mounting or for introducing surgical instruments into the interspace of the spine, such as a camera for viewing the inside of the interspace of the spine, or for any other surgical instrument such as a metal cutting tool or laser.

The transducer uses a single port which is called the transducer port. The transducer can be activated and active while a spinal fluid exchange device 90 exchanges spinal fluid. The spinal fluid exchange device 90 can handle cerebrospinal fluid so that it is drained and exchanged with an inflow of artificial cerebrospinal fluid. A dialyzer 95 can drain cerebrospinal fluid, treat (e.g., dialyzed of a substance) and re-circulate into the subarachnoid space.

If the pressure monitor is mounted to the patient, FIG. 8, the wireless data transmitter 70 may also a wireless signal 75 to a wireless data receiver 71 for display on a wireless data display 73.

While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but as exemplifications of the presently preferred embodiments thereof. Many other ramifications and variations are possible within the teaching of the invention. Additionally, any combination of the above examples may be possible. Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than the examples given. 

1. A spinal catheter comprising: a. an elongate shaft having a distal end and a proxial end; b. monitoring lumen connected to a monitoring port at a distal end, wherein the monitoring port is the first port; c. an inlet lumen formed on the elongate shaft and connected to an inlet port, wherein the inlet port is the second port; d. an outlet lumen having the same cross sectional area as the inlet lumen and connected to an outlet port, wherein the outlet port is the third port; e. wherein the distal end is adapted for placement in a spinal fluid pathway or cistern, particularly the lumbar cistern.
 2. The spinal catheter of claim 1, wherein the catheter has at least four ports total, organized in quadrant configuration wherein the fourth port is a spare port capable of receiving a surgical tool which passes through the spare port to an opening in the tip.
 3. The spinal catheter of claim 1, wherein a fourth port is a surgical tool port and receives a surgical tool.
 4. The spinal catheter of claim 1, further comprising a transducer mounted to the monitoring port, wherein the transducer forms the distal end of the spinal catheter.
 5. The spinal catheter of claim 4, wherein the transducer can transmit and collect electromagnetic radiation, in the ultrasonic, infrared range, and visible range.
 6. The spinal catheter of claim 4, wherein the transducer continuously monitors structural data of the spinal cord, including central canal size and parenchymal edema.
 7. The spinal catheter of claim 4, further comprising a biosensor mounted to the distal end of a port, wherein the biosensor monitors cerebrospinal fluid for physiological parameters, and information is sent to a subcutanous wireless transmitter for transmission to an external receiver.
 8. The spinal catheter of claim 4, wherein the transducer is an applanation pressure sensor.
 9. The spinal catheter of claim 4, wherein the transducer monitors change in spinal fluid pressure.
 10. The spinal catheter of claim 4, wherein the transducer monitors spinal dural compliance.
 11. The spinal catheter of claim 1, further comprising a biosensor mounted to the surgical tool port, wherein the biosensor monitors cerebrospinal fluid for physiological parameters, such as pH, glucose, protein, cell count and CSF gas values.
 12. The spinal catheter of claim 1, further comprising a fluid pump for delivery of a therapeutic substance to cerebrospinal fluid for treatment of a brain or spinal cord disease.
 13. The spinal catheter of claim 1, further comprising a spinal fluid data analyzer processing physiologic parameters of a patient which are monitored pre- and post-valsalva maneuver and compared to responses in control subjects.
 14. The spinal catheter of claim 1, further comprising a spinal fluid exchange device for exchanging cerebrospinal fluid with an inflow of artificial cerebrospinal fluid.
 15. The spinal catheter of claim 1, further comprising a dialyzer that drains cerebrospinal fluid, dialyzes it of a substance and re-circulates cerebrospinal fluid into subarachnoid space.
 16. The spinal catheter of claim 1, wherein the catheter has at least four ports total, wherein a fourth port is a surgical tool port and receives a surgical tool, further comprising a transducer mounted to the monitoring port, wherein the transducer forms the distal end of the spinal catheter.
 17. The spinal catheter of claim 16, wherein the transducer can transmit and collect electromagnetic radiation, in the ultrasonic, infrared range, and visible range.
 18. The spinal catheter of claim 16, wherein the transducer continuously monitors structural data of the spinal cord, including central canal size and parenchymal edema, wherein the transducer continuously monitors flow characteristics of the spinal cord, including blood and cerebrospinal fluid velocity, wherein the transducer is an applanation pressure sensor, wherein the transducer monitors spinal fluid pressure, wherein the transducer monitors spinal dural compliance.
 19. The spinal catheter of claim 16, further comprising a biosensor mounted to the surgical tool port, wherein the biosensor monitors cerebrospinal fluid for physiological parameters, such as pH, glucose, protein, cell count and CSF gas values, further comprising a fluid pump for delivery of a therapeutic substance to cerebrospinal fluid for treatment of a brain or spinal cord disease, further comprising a spinal fluid data analyzer processing physiologic parameters of a patient which are monitored pre- and post-valsalva maneuver and compared to responses in control subjects.
 20. The spinal catheter of claim 16, further comprising a spinal fluid exchange device for exchanging cerebrospinal fluid with an inflow of artificial cerebrospinal fluid, further comprising a dialyzer that drains cerebrospinal fluid, dialyzes it of a substance and re-circulates cerebrospinal fluid into subarachnoid space. 